Java Reference
In-Depth Information
// Java for Engineers
// Filename: FpComp
// Reference: Chapter 24
// Description:
//
Floating-pioint comparisons
// Requires:
//
Keyin class in current directory
import java.lang.*;
class FpComp
{
public static void main(String[] args)
{
double num1 = -0.0;
double num2 = 0.0;
double sqrPos = Math.sqrt(4.0);
double sqrNeg1 = Math.sqrt(-4.0);
double sqrNeg2 = Math.sqrt(-9.0);
// Comparing signed zeros using the == operator
System.out.println(“Using == to compare 0 and -0 ”);
if(num1 == num2)
System.out.println(“numbers are equal”);
else
System.out.println(“numbers are not equal”);
// Comparing using the equals() method
// First convert primtive doubles to Double objects
Double n1 = new Double(num1);
Double n2 = new Double(num2);
System.out.println(“Using equals() to compare 0 and -0");
if(n1.equals(n2))
System.out.println(“numbers are equal”);
else
System.out.println(“numbers are not equal”);
// Comparing NanS
Double sp1 = new Double(sqrPos);
Double sn1 = new Double(sqrNeg1);
Double sn2 = new Double(sqrNeg2);
System.out.println(“Using equals() to compare two NaNs ”);
if(sn1.equals(sn2))
System.out.println(“NaNs are equal”);
else
System.out.println(“NaNs are not equal”);
}
}
When the program executes the following output is produced:
